JP2512778Y2 - Full-speed standby operation pump - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to the standby operation of a vertical mixed flow or vertical spiral mixed flow rainwater pump mainly used for a rainwater / sewage confluence station in a large city. It is used to prevent the discharge of sewage below the operation permission water level of the rainwater pump when starting the pump in advance regardless of the water level.

[Prior Art] Conventionally, as shown in FIG. 3, in a sewage / rainwater merging type pump station equipped with a sewage pump A and a rainwater pump B, a sewage pump A on the left side and a rainwater pump B on the right side in the figure are shown. In each of the above, the operating water level is defined as follows. That is,
The starting water level of the rainwater pump B, that is, the drainable water level WL1 is
The water level is considerably higher than the starting water level WL0 of the sewage pump A, and is almost near the maximum water level HWL of the sewage pump A. The rainwater pump B started after the inflow of rainwater started, and when the inflow of rainwater decreased and the water level dropped to the normal water level NWL of the sewage pump A, the drainage was stopped by an electrical or mechanical control device. ing.

Generally, in the combined rainwater pump, once the water level of the suction water tank reaches the drainage permission level of the rainwater and drainage is started, even if the water level of the suction water tank falls to the operating range of the sewage pump, the rainwater pump will discharge the water to the river. Forgiven.

However, once the drainage is stopped, discharge into the river is not allowed unless the suction tank water level rises to the drainage permitted water level again.

At this time, the minimum operating water level of the rainwater pump B, that is, the water level of the suction water tank 1 is the normal minimum water level at which no air suction vortex is generated.
When operating below LWL, the minimum operating water level L
Below WL, the rotation speed of the pump is reduced or valve control is performed to prevent the generation of air suction vortices from the suction pipe.

As described above, in the conventional technique, since the control device is used abundantly, the equipment becomes expensive and there is a problem in reliability.

[Problems to be solved by the device]

Fig. 4 shows the operating water level when the full-speed standby operation pump is applied as a rainwater pump to the above pump station. In the figure, a full-speed standby operation pump C is a pump for sucking air from a through hole 5 provided in the suction pipe 4 through an air pipe 6 attached to the through hole 5 at a water level below a normal minimum operating water level LWL. Since the amount of drainage is automatically suppressed, it is not necessary to control the rotation speed of the pump 3 at a water level below the minimum operating water level LWL, but the drainage start water level, etc. are not properly determined. There was a problem.

That is, the drain start water level WL2 of the full speed standby operation pump C
Is near the tip of the impeller, the drainage stop water level WL3 is near the through hole 5 provided in the suction pipe 4, and both water levels
Since both WL2 and WL3 are located below the normal water level NWL of the wastewater pump A, there is a problem that the drainage is started and the wastewater is discharged at the rainwater pump drainage permission water level WL1 or lower, which has been set conventionally. there were.

The present invention is intended to provide a full-speed standby operation pump for rainwater that can perform full-speed standby operation and that does not discharge wastewater by not starting drainage at a water level below the drainage permission level of the rainwater pump that has been conventionally set. There is.

[Means for solving the problem]

In order to achieve the above-mentioned object, the present invention provides a through hole in the suction pipe on the impeller inlet side of a vertical axis rain water pump at a waste water combined rain water pump equipped with a waste water pump and a rain water pump. In a full-speed standby operation pump that opens above the maximum water level and has an air pipe that communicates with the outside air to enable full-speed standby operation without external control, a sewage pump set near the position of the through hole Of the rainwater pump located above the normal water level of the above, the impeller is positioned above the drainage allowable water level of the rainwater pump, and the suction pipe tip is to maintain a necessary gap between the tip and the bottom of the suction water tank. It is positioned at the normal level corresponding to the height from the bottom of the suction water tank set in step 3, and even if it is started based on rainfall information etc., the inflow of rainwater starts without external control and drainage is permitted. Until the water level is reached Without drainage, it is characterized in that to enable i.e. to avoid draining sewage.

In addition, when the drainage allowable water level of the rainwater pump is close to the normal minimum operating water level of the pump, an auxiliary air pipe equipped with a valve that is closed by the rainwater being sent into the discharge pipe is used as a suction pipe. It is attached to the through hole provided immediately before the impeller, and at the start of drainage, air is introduced from the auxiliary air pipe to alleviate abnormal vibration of the pump and excessive change in axial torque that occur at the start of drainage. I am trying.

[Action]

Since the present invention is configured as described above, the drainage state of the rainwater pump changes as follows.

Drainage starts when the water level rises to the tip of the rainwater pump blade, and the water level further rises as the inflow increases, and operation is performed within the maximum water level HWL. As the inflow of rainwater decreases and the water level approaches the normal level of the sewage pump, the rainwater pump increases the amount of air sucked from the air pipe through the through hole, and the drainage capacity gradually decreases. The position of the through hole is set so that when the water level reaches the normal water level of the sewage pump, air accumulation occurs at the lower part of the impeller of the rainwater pump and the drainage stops.

Therefore, even if the rainwater inflow starts due to rainfall and the rainwater pump is started in advance, the blade tip position of the rainwater pump is set above this level within the water level of the wastewater pump, so the rainwater pump Do not start draining. When the water level rises to the drainage permitted water level of the rainwater pump, the first drainage is started, but draining is performed while sucking air from the air pipe connected to the outside air connected to the above-mentioned through hole provided on the impeller inlet side suction pipe. Therefore, the process of gradual increase is followed.

Next, when the water level in the water tank further rises above the drainage permitted water level, the pressure at the through hole position increases as the water level rises, and the air inflow rate decreases, so the drainage rate gradually increases. Then, when the water level in the water tank reaches the minimum operating water level LWL of the pump, the inflow of air from the through hole is stopped, and operation is performed at the rated discharge amount.

On the other hand, when the inflow of rainwater decreases, the water level gradually approaches the minimum operating water level, and the amount of air sucked from the through holes increases, so the amount of drainage gradually decreases.

And if the suction water tank water level drops to the through hole, the water in the horizontal part of the air pipe connected to the through hole disappears and a large amount of outside air flows in through the air pipe, and the impeller inlet side is completely filled with air. The pumping function of the impeller disappears and the drainage stops. At this time, as described above, once the rainwater drainage permission level is reached and drainage is started by the rainwater pump, even if the suction water tank water level falls to the operating range of the wastewater pump (near normal water level NWL), Since the pump allows the discharge into the river, the position of the through hole where the drainage action stops does not have to coincide with the normal water level of the sewage pump.

The minimum operating water level of the rainwater pump is determined by the diameter of the pump, and the drainable water level is not necessarily the same because it is determined by the restrictions of the pumping station.

At the lowest operating water level of the rainwater pump, if the through hole provided in the suction pipe has a high water level in the aquarium and is sufficiently submerged, the effect of the flow velocity v is small, so an auxiliary force is provided immediately before the blade of the suction pipe. A through hole is provided, an auxiliary air pipe is attached to the through hole, an air valve that is closed by the flow of rainwater in the discharge pipe is attached to the tip of the air pipe, and air is introduced from the air pipe to temporarily stop drainage. The amount of drainage is reduced.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a vertical cross-sectional view of an in-tank vertical shaft / mixed flow pump showing an embodiment of the present invention, and FIG. 2 is a wastewater / rainwater combined pump station using the pump as a rainwater pump D. FIG.

In the figure, a through hole 15 is provided near the inlet of the suction pipe 14 of the pump 13, and the through hole 15 is always opened 16a above the highest water level HWL in the water tank 1 through the air pipe 16. There is. Further, an auxiliary through hole 17 is provided near the inlet of the impeller 12 of the suction pipe 14, and the through hole 17 is an auxiliary air pipe 18
Is attached to the air valve 20 attached to the pump discharge pipe 19. In the through hole 15 provided in the impeller inlet side suction pipe 14, the flow velocity v of the pumping water flowing through the through hole portion is from the vicinity of the through hole to the minimum operating water level, that is, harmful air suction vortex is generated from the suction pipe. Submerged depth that does not occur Height up to LWL h
The cross-sectional area of the suction pipe of the through-hole portion is set so as to generate a negative pressure corresponding to LWL in the figure is the normal minimum operating water level.

Since it is configured as described above, when waiting, when the water level in the suction water tank 1 rises to the drainage permitted water level WL1, drainage is started. At this time, negative pressure acts on the through hole 15 and the auxiliary through hole 17 due to the flow of the flow velocity v on the inflow side of the impeller 2.
Since a large pushing head acts on the through hole 15, there is almost no suction of outside air, and the auxiliary through hole is used exclusively.
Drainage starts when the intake of outside air occurs from 17 and the amount of drainage is reduced.

Next, when pumping water from the pump, the pump discharge pipe 19 is filled (filled with water), the air valve 20 attached to the discharge pipe 19 is closed, and the inflow of outside air from the auxiliary through hole 17 is stopped, and operation is started at a regular discharge amount. To do. At this time, since the amount of drainage gradually increases from the start of drainage until the air valve 20 is closed, abnormal vibration of the pump and excessive change in shaft torque that occur when drainage starts from the beginning at the rated drainage do not occur. .

Furthermore, when the suction water tank water level rises and reaches the minimum operating water level LWL, there is no suction of outside air from the through hole 15 and the auxiliary through hole 17, and the prescribed drainage is performed.

On the other hand, when the water level drops below the minimum operating water level LWL,
The outside air is sucked from the air pipe 16, and the air is sucked into the impeller 12 through the through hole 15. In this case, the intake amount of air increases and the discharge amount decreases as the water level decreases.

At this time, since the discharge pipe 19 is full (filled),
The air valve 20 remains closed so that the intake of outside air from the air tube 18 does not occur.

When the water level further decreases and reaches the water level in the vicinity of the through hole 15, a large amount of air is sucked in, an air pool is generated at the inlet side of the impeller 12, and the pump 13 completely stops drainage. Therefore, even in a rainwater / sewage confluence type pump station, stable standby operation can be performed without any external control.

Further, as shown in FIG. 2, since the normal water level NWL of the sewage pump A is usually set near the position of the through hole 15, the sewage water is not discharged from the rainwater pump D. However, once the rainwater drainage permission level is reached and drainage is started by the rainwater pump, even if the suction head level drops to the operating range of the sewage pump (near water level NWL), the rainwater pump discharges the water to the river. However, strictly speaking, the position of the through hole where the drainage action is stopped need not coincide with the normal water level of the sewage pump.

As described above, the minimum operating water level LWL shown in FIG. 1 is the submerged depth that does not generate harmful air suction vortices from the suction pipe 14, but the air pipe 16 and the through hole 15 for standby operation are of
Stable air inflow below LWL water level, abnormal noise,
It is provided for the purpose of avoiding vibration.

In addition, the air pipe 18 and the auxiliary through hole 17
Even if the water level of WL1 is equal to or higher than the above-mentioned LWL, air is introduced at the start of drainage to prevent excessive vibration and change in shaft torque. in this case,
The drainage permission water level WL1 is determined from the requirements of the station regardless of the minimum operating water level LWL of the pump.

Therefore, drainage permission water level WL1 and accordingly drainage start water level WL2,
When it is sufficiently lower than the minimum operating water level LWL of the pump, the effect of the flow velocity v in the suction pipe 14 is sufficient, and sufficient outside air to start gentle drainage is sucked in from the through hole 15, so the auxiliary penetration The hole 17 and the air tube 18 are unnecessary. The drainage permission water level is a water level determined by the convenience of the machine, and the drainage start water level is a water level determined by the installation level of the impeller. (In this case as well, the drainage start water level should be located higher than the drainage permission water level.) However, in reality, the settings are not made so that the drainage permission water level and the drainage start water level are substantially different, and the levels are almost the same. Can be said.

In each of the above-described embodiments, the structure in which one through hole 15 and one auxiliary through hole 17 are provided near the entrance of the impeller has been described, but the number of through holes is not limited to one, and a plurality of holes are provided. Of course, it is possible.

[Effect of device]

As described above, according to the present invention, the vertical rainwater pump of the combined sewage and rainwater type pumping station is provided with a through hole in the suction pipe on the impeller inlet side, and the through hole is opened above the maximum water level. An all-speed standby operation pump that enables an all-speed standby operation without external control by installing an air pipe that communicates with the outside air,
Position the impeller above the normal drainage water level of the wastewater pump set near the position of the through hole above the drainage permission water level of the rainwater pump located above, and suck the tip of the suction pipe into the air intake as usual. By arranging it below as much as possible so that no vortex is generated, without using expensive and complicated variable speed or movable blade pumps, when the water level suddenly rises at the beginning of rainwater inflow, the drainage level of the rainwater pump can be reliably discharged. Since the air is sucked from the through hole at the start of the drainage, the drainage does not start abruptly. In addition, when the water level suddenly drops when the inflow decreases, the operation control of the rainwater pump should be performed in order to reliably stop the rainwater drainage by the air sucked from the through hole at the drainage stop water level which is the same as the normal water level of the wastewater pump. It becomes possible to cope with the omitted full speed standby operation.

Further, in addition to the above configuration, by further providing an auxiliary air pipe equipped with a valve that closes when rainwater is fed into the discharge pipe immediately before the impeller of the suction pipe, the drainage allowable water level of the rainwater pump is increased. Even when the pump is close to the normal minimum operating water level, at the start of drainage, air can be introduced from the auxiliary air pipe to alleviate abnormal vibration of the pump and excessive change in axial torque that occur at the start of drainage.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an in-tank vertical shaft / mixed flow pump showing an embodiment of the present invention, and FIG. 2 is an explanatory view of a sewage / rainwater combined type plant using the present invention pump for a rainwater pump, FIG. 3 is an explanatory diagram of a conventional sewage / rainwater merging type plant, and FIG. 4 is an explanatory diagram of a sewage / rainwater merging type plant using a full-speed standby operation pump for the rainwater pump. 1 ... Water tank, 12 ... Impeller, 13 ... Pump, 14 ... Suction pipe, 15 ...
Through hole, 16 ... Air tube, 16a ... Opening, 17 ... Auxiliary through hole, 18
… Auxiliary air pipe, 19… Pump discharge pipe, 20… Air valve, HWL…
Highest water level, LWL ... Lowest operating water level, WL1 ... Drainage permission water level of rainwater pump, WL2 ... Drainage start water level, WL3 ... Drainage stop water level, WL0 ... Sewage pump start water level, NWL ... Normal water level.

Claims (2)

(57) [Scope of utility model registration request] 1. A vertical axis rainwater pump at a sewage / rainwater merging type plant equipped with a sewage pump and a rainwater pump in the same water tank,
A through hole is provided in the suction pipe on the impeller inlet side, and an air pipe that opens above the highest water level and communicates with the outside air is attached to the through hole.
In the full-speed standby operation pump that enables the full-speed standby operation without performing external control, the drainage permission level of the rainwater pump located above the normal water level of the sewage pump set near the position of the through hole above With the impeller positioned and the suction pipe tip positioned at a normal level, rainwater inflow will start without external control even if the engine is started based on rainfall information, etc. A full-speed standby operation pump which is characterized in that it is possible to prevent drainage, that is, to prevent drainage of wastewater until it reaches. 2. When the drainable water level of the rainwater pump is close to the normal minimum operating water level of the pump, an auxiliary air pipe equipped with a valve that is closed by the rainwater being sent into the discharge pipe is further provided. It was attached to the through hole provided immediately before the impeller of the suction pipe so that air would flow from the auxiliary air pipe at the start of drainage to moderate abnormal vibrations of the pump and excessive changes in axial torque that occur at the start of drainage. The full-speed standby operation pump according to claim 1, which is characterized in that.